Magnetic Resonance Imaging (MRI) and ultrasound are the two most widely used real-time in vivo imaging systems/techniques for guiding a biopsy device to a location within the body of a patient. Other techniques include fluoroscopy, radiography, computed axial tomography (CAT or CT), and positron emission tomography (PET). Once the device reaches the location of interest, within the body, a tissue sample is obtained with the device. The device with the sample is then removed from the body.
The state of the tissue sample (e.g., cancerous or normal) is then determined by histology. If the sample is abnormal (e.g., cancerous), it is then necessary to return to the site from which the sample was taken to treat the site. It is difficult however to reposition properly the patient and to return to the same location to allow treatment at the exact location of the abnormal biopsy.